In the existing drive devices of an illumination apparatus, the dimming control is usually performed for the illumination apparatus with a phase cut dimming method. The illumination apparatus, for which the dimming is controlled according to the phase cut dimming method, not only can effectively and quickly control the luminous brightness of the illumination apparatus and save the electrical energy to a certain extent, but also has a low cost due to the simple structure and manufacture of the drive device having the phase cut dimming function. The drive device having the phase cut dimming function not only has a high power factor, but also is compatible with a leading phase cut dimming circuit or a trailing phase cut dimming circuit. Besides, this drive device also can operate in a quick response (QR) mode, or operate in a boost-buck mode or in flyback mode. However, the existing drive devices having the phase cut dimming function will increase the power consumption of a bleeder circuit due to connection to a dimmer, and thereby increase the power consumption of the entire integrated circuit to bring about unnecessary power loss to the illumination apparatus.